3D PRINTED ORTHOTICS

A new way to design and 3D print custom prosthetics and orthotics could give amputees, stroke patients and individuals with cerebral palsy lighter, better-fitting assistive devices in a fraction of the time it takes to get them today.

ANN ARBOR – A new way to design and 3D print custom prosthetics and orthotics could give amputees, stroke patients and individuals with cerebral palsy lighter, better-fitting assistive devices in a fraction of the time it takes to get them today. Developed by the University of Michigan College of Engineering, the system is being implemented at the University of Michigan Orthotics and Prosthetics Center (UMOPC).

The U-M engineers and clinicians who designed the new cyber manufacturing system say that shortening the fabrication time for custom orthotics could make the process easier on custom assistive device users, who today must wait days or weeks to receive essential orthotics and prosthetics. The digital design and manufacturing process can also improve the devices’ precision, fit and function and improve consistency from one provider to the next.

Prostheses are devices used to replace a lost limb, while orthoses are braces used to protect, align or improve function or stability to injured limbs. Currently, the U-M team is focusing on ankle foot orthosis, which are often prescribed to stroke patients to help them regain their ability to walk. More than two-thirds of the 700,000 stroke victims in the United States each year require long-term rehabilitation, and many of them can be helped with custom orthotics. The devices can also help children with cerebral palsy, myelomeningocele and other conditions gain stability and walk more easily.

“Eventually we envision that a patient could come in in the morning for an optical scan, and the clinician could design a high quality orthosis very quickly using the cloud-based software,” said Albert Shih, a professor of mechanical and biomedical engineering at the University of Michigan and the lead on the project. “By that afternoon, they could have a 3-D printed device that’s ready for final evaluation and use.”

The new technique begins with a three-dimensional optical scan of the patient. The orthotist then uploads the scan data to a cloud-based design center and uses specially developed software to design the assistive device. Next, the software creates a set of electronic instructions and transmits them back to the orthotist’s facility, where an on-site 3-D printer produces the actual device in a few hours.

Jeff Wensman, director of clinical and technical services at UMOPC, says the new process is a major departure from current methods, which begin with wrapping fiberglass tapes around the patient’s limb. The tapes harden into a mold, which is then filled with plaster to make a model of the limb. Next, heated plastic is formed around the model in a vacuum forming process to make the actual device. The device is then hand-finished by smoothing the edges and attaching mechanical components like straps. It’s a labor-intensive process that requires a large shop and a highly trained staff. By contrast, the only on-site equipment required by the new process is a optical scanner, a computer and a 3-D printer. In the future, this could give even small clinics in remote areas the ability to provide custom orthotics and prosthetics.

The lighter weight of the 3-D printed devices stems from a technique called “sparse structure,” which can make orthotics that are partially hollow using a wavy internal structure that saves weight without sacrificing strength. Developed by U-M mechanical engineering PhD student Robert Chisena, sparse structure was initially intended as a way to print orthotics more quickly, but researchers quickly realized that it could make them better as well.

“Traditional hand-made orthotics are solid plastic, and they need to be a certain thickness because they have to be wrapped around a physical model during the manufacturing process,” Wensman said. “3-D printing eliminates that limitation. We can design devices that are solid in some places and hollow in others and vary the thickness much more precisely. It gives us a whole new set of tools to work with.”

Because the 3-D manufacturing process uses computer-based models rather than hand fabrication, it’s also more consistent than current methods. Any clinic with a 3-D printer could produce exactly the same device time after time. In addition, computer models of previous orthotics can provide doctors with a valuable record of how a patient’s shape and condition progress over time.

The current 3-D printing device is already turning out orthotics and prosthetics for testing; Shih says the team is working to demonstrate how it can reduce costs and improve service and efficiency. Eventually, they plan to make the system’s software and specifications freely available so that other healthcare providers can roll out similar systems on their own.

“In a sense, we’re building a recipe that others can use to build their own systems,” Shih said.

The project is funded by the National Science Foundation and America Makes, a partnership between industry, academia, government and others that aims to develop advanced manufacturing and 3-D printing capabilities in the United States. Software for the project is being developed by Altair and Standard Cyborg. Stratasys provided the 3-D printer for the project.

“Without America Makes and Manufacturing USA, we would not be able to bring a state-of-the-art 3D-printer to the prosthetics center with the traditional research project,” Shih said. “Without the National Science Foundation’s Partnership for Innovation and cyber manufacturing grants, we would not be able to have PhD engineering students working at UMOPC to develop the system. I am very blessed to have all three projects funded and started at the same time to create this first-of-its-kind demonstration site at UMOPC for the Michigan Difference in advanced manufacturing and patient care.

The University of Michigan School of Dentistry is one of 10 institutions in the country that has been selected by the National Institute of Dental and Craniofacial Research (NIDCR) to establish a center that will develop clinical applications in tissue engineering and regenerative medicine that have dental, oral and craniofacial tests.

The Michigan Regenerative Medicine Resource Center, as it’s official known, will be led by Drs. William Giannobile and David Kohn. Their education and expertise complement each other – Giannobile’s as a clinician/life scientist; Kohn’s as an engineer. Giannobile chairs the school’s Department of Periodontics and Oral Medicine. Kohn is a professor in the school’s Department of Biologic and Materials Sciences and a professor in the Department of Biomedical Engineering at the College of Engineering.

“The center will transform how clinicians in the not-too-distant future repair, reconstruct and regenerate dental, oral and craniofacial anomalies in patients due to injury or disease,” Giannobile says. “In recent years there have been major discoveries and advances in dentistry, medicine, biology, materials science, technology and other fields, and NIDCR wants the Michigan Center and similar centers around the country to find ways to use those advances so clinicians can then apply those discoveries to help their patients.”

Above are three-dimensional printed polymer scaffolds designed to promote bone and periodontal repair in the oral cavity. The design offers the potential to regenerate the different tissues teeth needed to treat teeth that have lost support due to the periodontal disease process. Photo by Jerry Mastey

Above are three-dimensional printed polymer scaffolds designed to promote bone and periodontal repair in the oral cavity. The design offers the potential to regenerate the different tissues teeth needed to treat teeth that have lost support due to the periodontal disease process. Photo by Jerry Mastey

Crucial to achieving that objective, Kohn says, will be establishing teams of multidisciplinary and interdisciplinary specialists from across the University of Michigan, industry and private practice. “These teams will be dedicated to selecting the most scientifically sound, clinically and commercially applicable strategies to regenerate oral tissues,” he says.

Historically, Kohn says, discoveries in a laboratory have progressed in a linear fashion, that is, they move forward one step at a time before being commercialized and used clinically. “We want to change that approach,” Kohn adds. “Our teams will take discoveries that show promise and provide the resources to advance the technologies to apply them more quickly than in the past.” This approach, he adds, is uniquely suited to Michigan’s broad scientific, clinical and engineering strengths, and interdisciplinary culture.

Giannobile says clinical teams will work with technical advisory groups and data centers to assess what might be feasible clinically. In the past, he says, scientists and clinicians have not always communicated to take advantages of scientific advances that can be used by dentists in a patient care setting.

Among the groups that will help the Michigan Regenerative Medicine Resource Center will be the Wyss Institute at Harvard, a multidisciplinary research institute that focuses on developing new materials with applications in health care, manufacturing and other areas, and the McGuire Institute in Houston which focuses on delivering clinical applications based on research using new or improved technologies.

The center was established with a $125,000 grant from NIDCR, the first step in what will be a two-step process. The next step involves submitting a proposal that could possibly lead to funding for as much as $10 million, sometime next summer.

3D printing is revolutionizing the world, and the field of medicine is no exception. U-M researchers are already printing replacement human body parts such as ears and noses. We asked Biomedical Engineering Professor Scott Hollister to explain the process to us, and what he believes the long-term outlook is for printing the human body.

ABOUT THE PROFESSOR: Scott Hollister is a professor of Biomedical Engineering at the University of Michigan College of Engineering. His research group, the Scaffold Tissue Engineering Group (STEG), develops biomaterial platform systems (termed scaffolds) for tissue reconstruction. The STEG specifically focuses on the computational design, manufacturing and pre-clinical testing of degradable scaffold material systems.

Every day, their baby stopped breathing, his collapsed bronchus blocking the crucial flow of air to his lungs. April and Bryan Gionfriddo watched helplessly, just praying that somehow the dire predictions weren’t true.

“Quite a few doctors said he had a good chance of not leaving the hospital alive,” says April Gionfriddo, about her now 20-month-old son, Kaiba. “At that point, we were desperate. Anything that would work, we would take it and run with it.”

Bioresorbable splint used for first time ever at the University of Michigan’s C.S. Mott Children’s Hospital, successfully stopped life-threatening tracheobronchomalacia, case featured in New England Journal of Medicine.

They found hope at the University of Michigan, where a new, bioresorbable device that could help Kaiba was under development. Kaiba’s doctors contacted Glenn Green, M.D., associate professor of pediatric otolaryngology at the University of Michigan.

Green and his colleague, Scott Hollister, Ph.D., professor of biomedical engineering and mechanical engineering and associate professor of surgery at U-M, went right into action, obtaining emergency clearance from the Food and Drug Administration to create and implant a tracheal splint for Kaiba made from a biopolymer called polycaprolactone.

On February 9, 2012, the specially-designed splint was placed in Kaiba at C.S. Mott Children’s Hospital. The splint was sewn around Kaiba’s airway to expand the bronchus and give it a skeleton to aid proper growth. Over about three years, the splint will be reabsorbed by the body. The case is featured today in the New England Journal of Medicine.

“It was amazing. As soon as the splint was put in, the lungs started going up and down for the first time and we knew he was going to be OK,” says Green.

Green and Hollister were able to make the custom-designed, custom-fabricated device using high-resolution imaging and computer-aided design. The device was created directly from a CT scan of Kaiba’s trachea/bronchus, integrating an image-based computer model with laser-based 3D printing to produce the splint.

“Our vision at the University of Michigan Health System is to create the future of health care through discovery. This collaboration between faculty in our Medical School and College of Engineering is an incredible demonstration of how we achieve that vision, translating research into treatments for our patients,” says Ora Hirsch Pescovitz, M.D., U-M executive vice president for medical affairs and CEO of the U-M Health System.

“Groundbreaking discoveries that save lives of individuals across the nation and world are happening right here in Ann Arbor. I continue to be inspired and proud of the extraordinary people and the amazing work happening across the Health System.”

Kaiba was off ventilator support 21 days after the procedure, and has not had breathing trouble since then.

“The material we used is a nice choice for this. It takes about two to three years for the trachea to remodel and grow into a healthy state, and that’s about how long this material will take to dissolve into the body,” says Hollister.

“Kaiba’s case is definitely the highlight of my career so far. To actually build something that a surgeon can use to save a person’s life? It’s a tremendous feeling.”

The image-based design and 3D biomaterial printing process can be adapted to build and reconstruct a number of tissue structures. Green and Hollister have already utilized the process to build and test patient specific ear and nose structures in pre-clinical models. In addition, the method has been used by Hollister with collaborators to rebuild bone structures (spine, craniofacial and long bone) in pre-clinical models.

Severe tracheobronchomalacia is rare. About 1 in 2,200 babies are born with tracheobronchomalacia and most children grow out of it by age 2 or 3, although it often is misdiagnosed as asthma that doesn’t respond to treatment.

Severe cases, like Kaiba’s, are about 10 percent of that number. And they are frightening, says Green. A normal cold can cause a baby to stop breathing. In Kaiba’s case, the family was out at a restaurant when he was six weeks old and he turned blue.

“Severe tracheobronchomalacia has been a condition that has bothered me for years,” says Green. “I’ve seen children die from it. To see this device work, it’s a major accomplishment and offers hope for these children.”

Before the device was placed, Kaiba continued to stop breathing on a regular basis and required resuscitation daily.

“Even with the best treatments available, he continued to have these episodes. He was imminently going to die. The physician treating him in Ohio knew there was no other option, other than our device in development here,” Green says.

Kaiba is doing well and he and his family, including an older brother and sister, live in Ohio

“He has not had another episode of turning blue,” says April. “We are so thankful that something could be done for him. It means the world to us.

A Michigan Engineering researcher has discovered that one common approach to growing blood vessels in tissues actually produces leaky tubes. He’s found a solution.